PROJECT SUMMARY/ABSTRACT The objective of the proposed trial, International Study of Comparative Health Effectiveness with Medical and Invasive Approaches-Chronic Kidney Disease (ISCHEMIA-CKD) Ancillary Study, is to determine the best management strategy for stable ischemic heart disease (SIHD) patients with advanced chronic kidney disease (CKD) [defined as estimated glomerular filtration rate (eGFR) <30 mL/min/1.73m2) or on dialysis] and moderate-severe ischemia. ISCHEMIA-CKD will be a prospective, multicenter, international, randomized, controlled trial, conducted as a trial within the main ISCHEMIA trial that will enroll 1,000 SIHD patients with advanced CKD with moderate-severe ischemia by stress imaging and ejection fraction e35%. The trial hypothesis is that for patients with moderate-severe ischemia on stress imaging, a routine invasive strategy (INV) with cardiac catheterization (cath) followed by revascularization plus optimal medical therapy (OMT) is superior to a conservative strategy (CON) of OMT, with cath and revascularization reserved for patients who fail OMT. The primary endpoint will be time to death from any cause or myocardial infarction (MI). Quality of life and cost-effectiveness will also be compared between the two strategies. Patients with CKD are more likely to die than reach end stage renal disease (ESRD) and are therefore considered coronary artery disease (CAD) risk equivalents. The prognosis of patients with advanced CKD is poor with a mortality rate as high as 50-70% at 4-years and is worse than that for patients who have cancers, heart failure, stroke or acute MI. Despite this high risk of death, ~80% of recent CAD trials exclude CKD subjects and most of the treatments aimed at reducing their events are therefore extrapolated from cohorts without CKD. Advanced CKD subjects are underrepresented in contemporary trials comparing revascularization with medical therapy in SIHD patients such as the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial, or the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial, making any assessment about the utility of revascularization plus medical therapy vs. initial medical therapy alone in ths cohort problematic. Limited observational studies have suggested a possible survival benefit of revascularization but yet it is rarely (10-45%) performed for fear of acute complications including contrast induced acute kidney injury, indicating substantial equipoise in current clinical practice As we prepare for the CKD boom with an aging population and increasing prevalence of diabetes and obesity, and if one of the major goals as set by Healthy People 2020 (improving survival and quality of life for people with CKD) is to be accomplished, a treatment strategy trial such as the ISCHEMIA- CKD trial is urgently needed to target a reduction in death and cardiovascular events in this high-risk population. The importance of this question to be addressed by ISCHEMIA-CKD is the reason it was ranked by the Institute of Medicine among the top 100 US priorities for comparative effectiveness research.